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T Matsuzawa

Publications and source records attributed to T Matsuzawa.

At least 19 recordsLinked to original sources
PubMed2004

Development of schematic face preference in macaque monkeys.

This study investigated schematic face preferences in infant macaque monkeys. We also examined the roles of whole and partial features in facial recognition and related developmental change. Sixteen infant monkeys, all less than two months old, were presented with two stimulus pairs. Pair A consisted of "face" and "parts," with the components representing facial parts (i.e. eyes, mouth, and nose). Pair B consisted of "configuration" and "linear," each including three black squares. In each pair, one of two stimuli represented a facial configuration, namely "face" and "configuration." Visual following responses toward each stimulus were analyzed. The results revealed an early preference for schematic faces in these nonhuman primates. Infants less than one month of age showed a preference only for a stimulus that contained only whole facial configuration (i.e. "configuration" in Pair B). One-month-old macaque infants showed a preference only for "face" but not for "configuration." This result means that their preference at that age was affected by both the shape of the components and the overall configuration. As the developmental change and the contribution of both facial features are similar to those in human infants, it may suggest that primates share common cognitive processes in early schematic face recognition.

Animals↗
PubMed2001

Capturing and toying with hyraxes (Dendrohyrax dorsalis) by wild chimpanzees (Pan troglodytes) at Bossou, Guinea.

Chimpanzees (Pan troglodytes verus) were observed capturing and toying with western tree hyraxes (Dendrohyrax dorsalis, Order Hyracoidea) at Bossou, Guinea. An adolescent female carried one hyrax for 15 hr, slept with it in her nest, and groomed it. The captive was not consumed. Nearby adults ignored the hyrax. In another case, two adolescent males timidly inspected a small hyrax. These observations indicate that the chimpanzees at Bossou do not regard the hyrax as a prey animal, supporting the idea that lack of opportunity does not seem to be the only reason that chimpanzees do not consume an individual of a potential prey species.

Animals↗
PubMed2001

Alterations of gene expression in endoderm differentiation of F9 teratocarcinoma cells.

During the endoderm differentiation of F9 mouse embryonal carcinoma cells, as induced by sodium butyrate (NaBu) or retinoic acid (RA), gene expressions of alkaline phosphatase (ALPase), pyruvate kinase (PKase) and 5' ribonucleotide phosphohydrolase (5'-Nase) were examined. The specific activity of ALPase was found to increase by 3.5-fold after 48 hr treatment with NaBu. In contrast, specific activity of PKase were decreased by 63%. Northern blot analysis revealed that the elevation of ALPase activity resulted from an increase in the level of liver/bone/kidney (L/B/K)-type ALPase mRNA and that the decrease of PKase activity was dependent on a reduction in the level of M(2)-PKase mRNA. Interestingly, when NaBu was removed from the culture medium, the levels of these mRNAs reverted to their original levels after 16 h. During these processes, the specific activity of 5'-Nase and the level of its mRNA remained unchanged. In contrast, when F9 cells were treated with RA, only the level of L/B/K-type ALPase mRNA increased. Lastly, we examined the issue of whether an increase in the level of ALPase mRNA is dependent on the transcriptional activation of the mouse L/B/K-type ALPase gene. Transient transfection assays using luciferase reporter constructs showed that the promoter activity increased as the result of treatment with RA but not with NaBu.

5'-Nucleotidase↗
PubMed2001

Liver injury suppressing compounds from avocado (Persea americana).

To evaluate the protective activity of fruits against liver injury, 22 different fruits were fed to rats with liver damage caused by D-galactosamine, a powerful liver toxin. As measured by changes in the levels of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST), avocado showed extraordinarily potent liver injury suppressing activity. Five active compounds were isolated and their structures determined. These were all fatty acid derivatives, of which three, namely, (2E,5E,12Z,15Z)-1-hydroxyheneicosa-2,5,12,15-tetraen-4-one, (2E,12Z,15Z)-1-hydroxyheneicosa-2,12,15-trien-4-one, and (5E,12Z)-2-hydroxy-4-oxoheneicosa-5,12-dien-1-yl acetate, were novel.

Alanine Transaminase↗
PubMed2001

Memory of movies by chimpanzees (Pan troglodytes).

How do animals remember what they see in daily life? The processes involved in remembering such visual information may be similar to those used in interpreting moving images on a monitor. In Experiment 1, 4 adult chimpanzees (Pan troglodytes) were required to discriminate between movies using a movie-to-movie matching-to-sample task. All chimpanzees demonstrated the ability to discriminate movies from the very 1st session onward. In Experiment 2, the ability to retain a movie was investigated through a matching-to-sample task using movie stills. To test which characteristics of movies are relevant to memory, the authors compared 2 conditions. In the continuous condition, the scenes comprising the movie progressed gradually, whereas in the discrete condition, the authors introduced a sudden change from one scene to another. Chimpanzees showed a recency effect only in the discrete condition, suggesting that composition and temporal order of scenes were used to remember the movies.

Animals↗
PubMed2000

Activation of rho through a cross-link with polyamines catalyzed by Bordetella dermonecrotizing toxin.

The small GTPase Rho, which regulates a variety of cell functions, also serves as a specific substrate for bacterial toxins. Here we demonstrate that Bordetella dermonecrotizing toxin (DNT) catalyzes cross-linking of Rho with ubiquitous polyamines such as putrescine, spermidine and spermine. Mass spectrometric analyses revealed that the cross-link occurred at Gln63, which had been reported to be deamidated by DNT in the absence of polyamines. Rac1 and Cdc42, other members of the Rho family GTPases, were also polyaminated by DNT. The polyamination, like the deamidation, markedly reduced the GTPase activity of Rho without affecting its GTP-binding activity, indicating that polyaminated Rho behaves as a constitutively active analog. Moreover, polyamine-linked Rho, even in the GDP-bound form, associated more effectively with its effector ROCK than deamidated Rho in the GTP-bound form and, when microinjected into cells, induced the anomalous formation of stress fibers indistinguishable from those seen in DNT-treated cells. The results imply that the polyamine-linked Rho, transducing signals to downstream ROCK in a novel GTP-independent manner, plays an important role in DNT cell toxicity.

3T3 Cells↗
PubMed2000

Imitation of intentional manipulatory actions in chimpanzees (Pan troglodytes).

In this study, the authors investigated the understanding of other's actions in 5 adult chimpanzees (Pan troglodytes). A human demonstrated an attempt to open different containers. Each container required a different motor pattern to open it. Along with the container, a 2nd object was made available. After a free play period in which the chimpanzees' natural behaviors toward the objects were recorded, the authors tested the following 2 phases: The demonstrator (a) tried but failed to open and (b) opened the container successfully, with 1 of 2 alternative strategies, either using an "irrelevant tool" or by hand. The chimpanzees did not reproduce the demonstrator's motor patterns precisely but did reproduce the demonstrated strategies in both phases. These results suggest that chimpanzees anticipate the intentions of others by perceiving the directionality and causality of object(s) as available cues.

Animals↗
PubMed2000

The exacerbating effect of insulin-induced hypoglycemia on spontaneous peripheral neuropathy in aged B6C3F1 mice.

The effect of insulin-induced hypoglycemia on spontaneous peripheral neuropathy in aged mice was examined. Ninety-five-week-old female B6C3F1 mice were infused subcutaneously for 2 weeks with 40 or 80 IU/kg/day of insulin with a micro osmotic pump. Blood glucose level was decreased during the infusion (4.3-6.8 mmol/L in mice receiving 40 IU/kg/day of insulin or 2.4-5.4 mmol/L in mice receiving 80 IU/kg/day of insulin versus 6.5-7.6 mmol/L in control mice). In histopathological examination, axonal degeneration and/or remyelination were observed in a small number of nerve fibers of control mice. Similar nerve fiber lesions were observed in mice receiving 40 IU/kg/day of insulin, whereas severer lesions with an increase in segmental axonal degeneration of nerve fibers were observed in 4/7 mice receiving 80 IU/kg/day of insulin. These findings suggest that spontaneous peripheral neuropathy in aged mice is exacerbated by sustained hypoglycemia induced by insulin treatment.

Animals↗
PubMed1999

Factors influencing imitation of manipulatory actions in chimpanzees (Pan troglodytes).

The purpose of the study was to investigate what kind of factors determine the degree of difficulty for chimpanzees (Pan troglodytes) when they imitate actions. Five adult chimpanzees were instructed to perform 48 arbitrary manipulatory actions consisting of different bodily motor patterns and object directionality. Results showed that actions in which an object is directed toward another external location (another object and one's own body) were easier to perform than those that involved manipulating a single object alone. Actions involving unfamiliar motor patterns were more difficult to perform than those involving familiar motor patterns that were already present in the subject's repertoire. Error responses were characterized as perseverative repetition of previously instructed actions. These findings suggest that chimpanzees find the directionality of manipulated objects a more salient cue than details of the demonstrator's body movements performing the manipulation.

Animals↗
PubMed1999

Identification of functional domains of Bordetella dermonecrotizing toxin.

Bordetella dermonecrotizing toxin (DNT) stimulates the assembly of actin stress fibers and focal adhesions by deamidating Gln63 of the small GTPase Rho. To clarify the functional and structural organization of DNT, we cloned and sequenced the DNT gene and examined the functions of various DNT mutants. Our analyses of the nucleotide and amino acid sequences revealed that the start codon of the DNT gene is a GTG triplet located 39 bp upstream of the reported putative initiation ATG codon; consequently, DNT contains an additional 13 amino acids at its N-terminal end. All of the N-terminally truncated mutants were found to modify Rho. The shortest fragment of DNT possessing the Rho modification activity consists of amino acids from Ile1176 to the C-terminal end. This fragment overlaps the region homologous to Escherichia coli cytotoxic necrotizing factors (CNFs), which show activity similar to that of DNT. The introduction of a mutation at Cys1305 located in the highly conserved region between CNFs and DNT eliminated the activity, indicating that this domain is the catalytic center of DNT. The N-terminal fragment (1 to 531) of DNT failed to modify Rho but reduced the DNT-induced polynucleation in MC3T3-E1 cells when simultaneously added with the holotoxin, suggesting competitive inhibition in the receptor-binding or internalizing step. Our finding that DNT consists of an N-terminal receptor-binding and/or internalizing domain and a C-terminal catalytically active domain may facilitate analysis of the overall action of the toxin on the mammalian target cells.

Amino Acid Sequence↗
PubMed1999

Evaluation of ready-to-use liquid reagents for clinical chemistry in laboratory animals.

We evaluated the ready-to-use liquid reagents for clinical chemistry (6 tests), to assess their suitability for use in the toxicology laboratory setting. Hitachi 736 automated analyzer was used for the analyses. The evaluation included the following studies: Precision, Linearity, Effects of interference substances such as hemolytic hemoglobin, bilirubin, turbidity to the analytical values and correlation to the solid reagents, which are prepared each time they are needed. The precision and linearity data were within the reagents' specifications. Results of comparison of the liquid reagents and the solid reagents in analyzing plasma samples of rats, dogs and monkeys were generally good except for a bias in results for GOT and GPT, regardless of the animal species tested. It is concluded that these types of liquid reagents can be used in clinical pathology examinations in animal studies.

Animals↗
PubMed1998

Use of leaves as cushions to sit on wet ground by wild chimpanzees.

A new type of tool use, leaf cushion, by wild chimpanzees (Pan troglodytes verus) at Bossou, Guinea, was found. We report two cases: one is indirect evidence; the other is direct observation of a chimpanzee who used the tool. Both cases indicate that chimpanzees used a set of leaves as a cushion while sitting on wet ground. Chimpanzees at Bossou show various kinds of tool use, some of which are unique to the community. Most of these behavioral patterns are substance tool use for obtaining food, as at other study sites. The use of leaves as a cushion adds to the few instances of nonsubstance, elementary technology seen used by wild chimpanzees.

Animals↗
PubMed1998

Cerebral blood flow correlated with carotid blood flow in neurologically normal elderly with severe white matter lesions.

Previous studies of white matter signal hyperintensity (WMSH) on T2-weighted MRI (magnetic resonance imaging) have shown it to be related to decreased cerebral blood flow (CBF). However, there have been few studies on the relationship of WMSH and the internal carotid blood flow (CaBF). Doppler ultrasound sonography is widely used for evaluation of CaBF. We analyzed the relationship between CBF, CaBF, and WMSH. The subjects had not suffered cerebral ischemic episodes although they had some risk factors for stroke. They received MRI and were classified into three groups, i.e. mild, moderate, and severe WMSH. The % stenosis of the internal carotid artery (ICA) was measured with angiography. Doppler sonography was used to measure the mean bilateral CaBF. The oxygen-15 steady-state technique and PET (positron emission tomography) were used to measure CBF. There were significant correlations between the % stenosis of ICA and the ipsilateral CaBF and between the % stenosis of ICA and hemispheric CBF. There was a significant relationship between CBF and CaBF in the severe WMSH group, remaining significant after partialling out of the effects of the % stenosis. This indicated that an atherosclerotic change of the cerebral artery occurred in a way that carotid vascular resistence and cerebrovascular resistence were 'proportional'. Copyright Rapid Science Ltd

Journal Article↗
PubMed1998

[Studies on antioxidant effects of Hypsizigus marmoreus. II. Effects of Hypsizigus marmoreus for antioxidant activities of tumor-bearing mice].

The in vivo effect of Hypsizigus marmoreus on the plasma antioxidant status of tumor-bearing mice was examined. Female DBA/2 mice treated with subcutaneous injection of 3-methylcholanthrene were fed on a basal diet (CE-2) or CE-2 containing 5% fruit bodies of the mushroom for 76 weeks. Antioxidant activities (AOA) of mice with tumor were significantly higher than those of mice without tumor. The high levels of AOA were attributable to the increase of high molecular weight AOA in the plasma. A similar increase in plasma AOA was also observed in sarcoma-180 solid tumor-bearing mice. The mushroom feeding exhibited a potent antitumor effect and caused a significant decrease in lipid peroxide levels (as thiobarbituric acid reactive substances; TBARS). These results suggest that the increase of AOA in the plasma of tumor-bearing mice is one of the mechanism of cancer preventive effects and also suggest that Hypsizigus marmoreus might play a role in decreasing TBARS by controlling AOA induction.

Agaricales↗
PubMed1998

A micromethod for protein assay using a light microscope.

A micromethod which utilizes a protein-dye binding reaction on an acetate membrane and a light microscope with an automatic exposure instrument has been developed for measuring small amounts of protein from limited biological materials. After discoidal cellulose acetate membranes (2.0 mm diameter), which absorbed 0.5 microliter of protein solution containing 0.2-2.0 micrograms of protein, were stained with Coomassie Brilliant Blue G-250, they were examined by a light microscope with an automatic exposure instrument. A linear relation was confirmed between the intensity of dye binding to protein and exposure time under specific optical conditions.

Animals↗